Safety installation for preventing pollution by pipelines

ABSTRACT

A safety installation for preventing pollution by pipelines, is provided with at least one sector equipped with a jacket of plastic material, the jacket surrounding the pipeline and being sealed at its ends on the latter, with the annular gap formed between the pipeline and its jacket containing a fluid and inserts and spaces. At least one vessel is provided for collecting the evacuated flow and liquid presence detector which gives a warning and remotely controls operations. A fluid-tight hollow space contains a gas under a pressure different from atmospheric pressure and connects the interior of at least one vessel to a crack in the pipe wherever the crack occurs. Instruments permanently monitor the tightness of the space, which comprises at least one perforated gap. Near each vessel is a liquid presence detector and every horizontal run gap of the space is filled with water. The jacket is pierced by at least one perforation, and there is a chimney surrounding the perforation. A channel leads into the chimney above the level of water and leas to a vessel to form part of the space. Every inclined run gap of the space is perforated at a low point in its jacket, and the channel surrounding the perforation and leading to the vessel forms part of the space.

United States Patent 91 Wittgenstein 1March 20, 1973 I541 SAFETYINSTALLATION FOR PREVENTING POLLUTION BY PIPELINES I [76] Inventor:Gerard Francis Wittgenstein, 29

Champrond Way, Lausanne, Switzerland [22] Filed: Sept. 2, 1970 [21]Appl. No.: 68,949

[30] Foreign Application Priority Data Sept. 2, 1969 Switzerland ..13849'69 [52] US Cl. ..138/l04, 73/491, 137/312, 138/111, 285/93 [51] Int. Cl..Fl6l 55/00 [58] Field of Search ..73/40, 40.5 R, 40.5 A, 49.1;137/236, 312, 558; 138/104, 111, 112,114; 174/11 R; 285/13, 93; 340/242Primary Examiner-Houston S. Bell, Jr. Attorney-Holman & Stern [5 7ABSTRACT A safety installation for preventing pollution by pipelines, isprovided with at least one sector equipped with a jacket of plasticmaterial, the jacket surrounding the pipeline and being sealed at itsends on the latter, with the annular gap formed between the pipeline andits jacket containing a fluid and inserts and spaces. At least onevessel is provided for collecting the evacuated flow and liquid presencedetector which gives a warning and remotely controls operations. Afluid-tight hollow space contains a gas under a pressure different fromatmospheric pressure and connects the interior of at least one vessel toa crack in the pipe wherever the crack occurs. Instruments permanentlymonitor the tightness of the space, which comprises at least oneperforated gap. Near each vessel is a liquid presence detector and everyhorizontal run gap of the space is filled with water. The jacket ispierced by at least one perforation, and there is a chimney surroundingthe perforation. A channel leads into the chimney above the level ofwater and leas to a vessel to form part of the space. Every inclined rungap of the space is perforated at a low point in its jacket, and thechannel surrounding the perforation and leading to the vessel forms partof the space.

6 Claims, 8 Drawing Figures PATENTEB MR 2 0 m5 SHEET 10F 2 INVENTOR 0mmmnuswmcsm RY MW 4 m ATTORNEYJ FIG?) lNVENTOR GERARD FRANEIS WIUGENSTEINATTORNEYS SAFETY INSTALLATION FOR PREVENTING POLLUTION BY PIPELINESBACKGROUND OF THE INVENTION This invention relates to a safetyinstallation for preventing pollution by pipelines, particularly thoseused for transporting liquid hydrocarbons; it is applica-. ble to anypipeline, but particularly to underground or submarine pipelines,whether made of steel, plastic, or any other material.

It may be applied by equipping at least one sector of an existingpipeline or of a pipeline to be built; each equipped sector comprises afluid-tight jacket of plastic material which surrounds the pipe andwhich at its ends is sealed on the latter; it is these seals whichdelimit the sector. The annular space formed between the jacket and thepipe contains a fluid and inserts. The installation also comprises atleast one vessel receiving the evacuated flow and a liquid presencedetector which gives an alarm and remotely controls operations.

The four essential objects of the invention are to ensure reliableprevention of pollution of the environment due to leakage of ahydrocarbon through cracks in the pipe, to evacuate the leakage flowwithout delay to a vessel, to signal almost instantaneously theexistence of a crack, and finally, as soon as'the pipe is cracked, toeffect remote control of operations by which the dynamic pressure in thepipe is cancelled; an additional object is to apply the invention notonly to underground pipes but also to submerged pipes.

Pollution preventing equipment has already been disclosed for twooldtypes of installation, namely the type having a closed annular gap inwhich the polluted liquid consequently collects,,and the type having anopen annular gap which therefore discharges the flow to a vessel. Thefirst type is represented by British Patent No. 886,674 and the secondby Swiss Patent No. 468,590.

The accumulator type is inapplicable for various reasons including inparticular the fact that a leak may quickly give rise to dangerouspressure in the accumulator gap, thus making it necessary to constructthe jacket of a steelmaterial, and this more than doubles the moment ofresistance of the pipeline equipped in this manner; the pipeline is thusmade very rigid and can no longer bend to adapt itself to thesinuosities of the layout.

The evacuator type known in the present state of the art is applicableonly to runs having a high point, which excludes horizontal lengths ofthe line; in addition, this known type of installation does not providesecurity. The annular gap is, in fact, in communication with theatmosphere, so that leaking oil flows into the, ground through thiscommunication; the lifting of the oil towards a long and expensivedischarge manifold changes nothing in this respect, particularly as thetightness of this pipe, which is at atmospheric pressure, is neithercontrolled nor controllable; moreover, the suitability of this knowninstallation is questionable because the hydrostatic pressure ingradients may attain a dangerous level. Such an installation isexpensive because of the counter-measures of dividing gradients which itentails and is therefore inapplicable.

The present invention is intended to overcome all these disadvantages.It eliminates in fact the discharge manifold and also the pressure ingradients and the resulting lack of safety; the connection of the gapsto the atmosphere and the pollution which results therefrom; anylengthening of the path of flow .to the vessel and any stagnation onthat path; it increases the mean speed of flow; it is applicable to anyprofile, whether horizontal or a gradient; subsidiarily, it is alsoapplicable at sea and in docks. Consequently, the invention is believedto constitute a remarkable improvement compared with the prior art.

SUMMARY OF THE INVENTION According to the present invention, the flow ofa leakage follows, from the crack to the vessel, a path situatedentirely in a leakproof space which is under a different pressure fromatmospheric pressure,- thetightness of such space being permanentlyensured and the space being filled with gas except on horizontal runs,in which it is filled with liquid.

The flow progresses towards the vessel through forced circulation in theliquid runs and through gravity in the other parts of its path.

Such are the functional characteristics of the invention.

The aforesaid forced circulation entails only'a low loss of head;moreover, it is sufficient to provide more than one chimney to lower thedelivery pressure to the safety threshold of the material of which thejacket is made; this permits the use of inexpensive materials.

It is observed that a gap, whether horizontal or inclined, may beslightly undulating, which does not in any way affect its generalclassification as horizontal or inclined; a modification or even areversal of the inclination does not terminate the inclined gap, which-is terminated only by a horizontal gap.

An installation according to the invention is charac terized in that afluid-tight hollow spacecontaining a gas under a pressure different fromatmospheric pressure connects the interior of at least one vessel toacrank in the pipeline, wherever this crack occurs, in

that instruments permanently verify the tightness of said space, in thatthe latter comprises at least one perforated gap, in that it contains aliquid presence detector situated near each vessel, in that everyhorizontal gap of said space is filled with water and that its jacket ispierced by at least one perforation, in that the chimney surrounding theperforation and the channel which leads into said chimney above thewater level and leads to a vessel form part of said space, in that everyinclined gapof said space is perforated at a low point in its jacket,and in that the channel surrounding said perforation' and leading to thevessel forms part of said space.

In general, a sector comprises a plurality of gaps; each horizontal gapis connected to the inclined-ad'- jacent gap by a selective transferdevice which retains static water but permits passage of a flow from thehorizontal gap to a vessel.

The selective transfer device consists of the chimney, its channel, andpartitioning betweenthe gaps containing different fluids; the channelusually ends either at the adjacent gas-filled gap or at the fillingpipe of'its vessel; this vessel at the bottom of the gradient is thenalso used for the flow coming from the horizontal gap; the fillingpressures of the water and the gas are then the same.

A special but less advantageous version consists in leading the channelinto a vessel which is specific to the horizontal gap; in this casethese pressures may be different.

It is observed that it is easier to pressurize the gas slightly than toreduce it below atmospheric pressure.

Instruments such as probes and pressure gauges may, for example, besuitable for permanently verifying or automatically verifying at shortintervals the tightness of the fluid-tight space; it is for this reasonthat the pressures of the water and gas are different from atmosphericpressure.

The water is preferably subjected to demineralization treatment and madenon-corrosive and the gas is an inert gas.

Other characteristics will be appreciated from the description whichfollows.

The jacket is preferably of plastic material and is made in situ, eitherin the form of two half-shells or in a single piece, which is slit, bythe process described in Swiss Patent No. 468,950 of the applicant; itmay be advantageous for short jacket elements provided with chimneys,chambers, and perforations to be prefabricated, optionally in two parts.

Inserts, known in themselves from the aforesaid patent, are disposed inthe annular gap between the pipe and the jacket; they have the dualpurpose of facilitating the centering of the latter and receiving theimpact of the jet of liquid escaping through a crack; they formlongitudinal channels; it is advantageous for the inserts to have theform of sheets of plastic material or metal, transversely corrugated, bywhich the pipe is surrounded and which are held in place by straps or byadhesive bonding.

A new improvement of these inserts consists in perforating the flanks oftheir corrugations; these perforations, which are for example staggered,provide intercommunication between the channels and give rise to passageresistances which absorb the kinetic energy of the flow.

According to the present invention, accessories may be placed in thegaps, particularly metallic elements providing cathodic protection forthe pipe against corrosion from the water in the gap, even though it hasbeen demineralized; these accessories, connected by a wire to the pipe,are advantageously disposed between the inserts and the jacket.

Leaks in the pipe may be located by means of locating cables of the typedescribed in Swiss Patent No. 426,394 of the applicant; these cables areto be extracted through access chambers disposed along the sector; ifthe latter is very long it is convenient to dispose successive cablesbetween two successive chambers or between an access chamber and achimney.

The electric contacts of these instruments and appliances, such asdetectors, probes, contact type pressure-gauges, electrically controlledvalves, relays, and so forth, are connected by wires grouped in electriccables to a central panel.

From the central panel the warning is given in the event of a leak,while at the same time operations can be remotely controlled for thepurpose of rapidly reducing the dynamic pressure in the pipe; theseoperations relate particularly to the pumps and valves.

In a special version, the vessel may be isolated by a I BRIEFDESCRIPTION OF THE DRAWINGS FIG. 1 shows diagrammatically, and withoutthe limit seals, a longitudinal view of a pipeline sector; thehorizontal and inclined runs, some of which are undulating, that is tosay of the type occurring in practice, can be seen therein.

FIG. 2 shows on a larger scale the zone of a perforation at the bottomof an inclined gap connected to a horizontal gap; the filling pipe isconnected to the vessel without a valve being inserted, so that in thisversion the vessel forms part of the controlled fluid-tight space. Thisfigure also shows an example of the selective transfer device, namelythe chimney and its channel towards the inclined gap, with thisarrangement being mounted in parallel on the partition.

FIG. 3 shows on a larger scale a double perforation at the bottom pointsof two oppositely inclined runs separated by a partition; in thisversion a valve is disposed on the pipe filling the vessel, so that thelatter can be isolated. It may be observed that in practice it wouldhave been considered that a profile of this kind which has no horizontalrun has only a single bottom point; partitioning would therefore nothave been effected and a single perforation would be sufficient.

FIG. 4 is a section along the line X-X of the partition shown in FIG. 3.

FIG. 5 is a section along the line YY'of the pipe shown in FIG. 3.

FIG. 6 shows on a larger scale a horizontal gap connected by a selectivetransfer device to the top of an inclined gap.

FIG. 7 shows on a larger scale the top of the undula-. tion formed bytwo gradients; there is no horizontal run and therefore no specialjunction and FIG. 8 is a plan view of the part of FIG. 1 showing the twofilling pipes for a single vessel.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, thereis shown a pipeline 1 with a jacket 2, horizontal runs 3, inclined runs4, a V shaped run 7, and an inclined run 5, which is also undulating.The ground level is shown at 33; several chambers for providing accessto the gaps are also shown.

The prefabricated segments 6, 7, 8, 8', 8", and 9 are preferablydisposed in bricked excavations designated hor /i /i as-filled gap 10 ofthe runs 9 and which follow one another, with the first beingprefabricated and the second made in situ. The perforation of the jacketof the inclined run is at 12", and filling pipe 15" of vessel 16" feedsbox 19" through a detection normally open valve as soon as the flowreaches the perforation. In the path of the filling pipe there is showna lateral chamber 18'', which consequently does not form an obstacle,and which contains one end 30" of a locating cable.

A chimney 35 and a channel 39 branched off from a partition 13constitute the selective transfer device; the partition in fact preventsthe static water from the horizontal run gap from being transferred tothe gap 10, while in the case of a leak in the horizontal run of thepipeline, the gap water is immediately forced back and water level 38rises instantaneously in the chimney; the water is then automaticallytransferred through channel 39 into the gas gap 10, from which it flowsthrough the action of gravity through the perforation 12" and, followingthe pipe 15", towards the detection box 19" and the vessel 16". The pathof the liquid towards the vessel 16" is defined by the gap 11, thechimney 35, the channel 39, the gap 10, the perforation 12", and thefilling pipe 15".

A crack in the inclined pipeline has the effect of filling the samevessel; the selection of the defective run may be effected by asignalling probe situated in the chimney, while another probe, at 36,permanently checks the tightness of the jacket of the horizontal run;inthe event of water leakage, the level 38 falls and this probetransmits a signal through a cable 37 to a central panel,

' The fluid-tight box 19" contains in particular a device 21" forverifying the pressure of the gaseous fluid; this monitoring means isconnected by wires 22" tothecentral panel; the box also contains aliquid presence detector such as, for example, that represented by a rod24" on which a float 23" slides. This float contains a magnet whichopens or closes a contact25" connected by electric wires 26" to thepanel. A pressure gauge 27", which may be outside the box and even at adistance therefrom, also permits permane nt monitoring of gas pressure.The liquid presence detector gives the warning and through its contactsor those of a relay it remotely controls the operations of pumps. andvalves, which rapidly bring about a drop in the dynamic pressure in thepipeline.

The annular gaps 10 and 11, the channel 39, the chimney 35, the pipe15", the vessel 16", and the box 19, constitute the controlled space;all this space is placed under the same pressure, which is slightlyhigher than atmospheric pressure. Theoretically the space could also besubjected to a subatmospheric pressure.

When an oil leak occurs in the run 5 of the pipeline,

this oil penetrates into the gap 10, from which it flows by gravity intothe vessel 16" after having passed through the perforation 12" andfollowed the path of the filling pipe 15"; before reaching the vessel 16it fills the box 19" and operates the float 23". The path of flowof thisleakage to the vessel 16 is defined by the gap, 10, the perforation 12",and the filling pipe 15".

, Forthe sake of simplification of the drawings, the inserts are notshown in FIG. 2, but they are seen in section in FIG. 5; in the versionillustrated by way of example inserts 14 are all connected together,while at 30 which leaks out is carried to the vessel, from which it is Ipumped; moreover, its devices detect any oil leakage without delay andinitiate operations by remote control; finally, the tightness of thejacket and more generally of the fluid-tight space is permanentlymonitored. For these reasons the invention fulfils its aims.

Referring especially to FIGS. 3 and 4, known ele- I ments are found oncemore; the gas-filled gaps l0 and 14 are here separated by a partition13. Each gap is perforated, one of them at 12 and the other at 12'; thevessel filling pipe 15 receives, upstream of avalve 17, the pipe 15which cooperates with the gap 14 and the perforation 12; a detection box19 and 19' respectively is associated with each pipe. A flow path iscon? stituted by the gap 14, the perforation 12', the pipe 15'.,

and the pipe 15; another flow path is constituted by the gap 10, theperforation l2, and the pipe 15.

In the version provided with a valve, various cases of operation can beconsidered; for example, the vessel is uncovered, in which case isnormally closed and opens only under remote control through the actionofa relay operated by one of the probes 24 or 24 as a result of thearrival of liquid. In another mode of operation the vessel is submerged;the valve is then normally open and is closed by remote control only ifthe vessel is emptied; the valve then isolates the installation.

In FIG. 6 there are found once again the elements known from thedescription of the previous figures. Ends 30 and 40 of crack locatingcables have been rolled into rings to facilitate their affixing.Referring to FIG, 6 at the same time as FIGS. 1 and 3, it is seen thatthe path of flow towards the vessel 16 is defined by the gap 11, thechimney 35', the channel 39', the gap 10, the perforation 12, and thepipe 15.

Finally, in FIG. 7 known elements are found again.

The invention is advantageously applied, whatever the profile of thelayout, in all cases where the law or public welfare require a ban onunderground or maritime pollution, since a warning and operationsimmediately follow a leakage in the pipeline.

What I claim is:

1. In combination, a pipeline and a safety installation for preventingpollution of the pipeline environment through cracks in that pipeline,said combination com prising a pipeline section defining a plurality ofruns, a continuous jacket surrounding said pipeline section and sealedat its ends thereto, spacing means having channels therein providing anannular gap between said pipeline section and said jacket along whichliquid leaking from said pipeline section can flow, fluid tightpartitions dividing said annular gap into horizontal water-filled runsin which the water flows by repelling action of leakage liquid, andinclinedadjacent gasfilled runs, in which the liquid flows by gravity,the water and gas in said runs being at the same constant pressure,which slightly exceeds atmospheric pressure, each said gas-filled runhaving at its lower end a leakage pipe connected to an individual closedcollecting vessel situated at a still lower level and also to a detectordevice which is reactive immediately to liquid in said leakage pipe,said gaps, said leakage pipe and said collecting vessel forming a sealedenclosure, and selective transfer devices acting to by-pass saidpartitions, each transfer device comprising a chimney partially filledwith water of a horizontal run and communicating over said water leverwith an inclined run.

2. The safety installation for pipelines as claimed in claim 1 includinga short conduit between the chimney and the inclined run providing thecommunication over the water level with an inclined run, and instrumentspermanently monitoring the fluid tightness of said enclosure.

3. The safety installation for pipelines as claimed in claim 1 in whichthe liquid filling'the channels of the annular gap of the horizontal runis demineralized water and the gas filling the channels of the annulargap of the inclined run is an inert gas.

4. The safety installation for pipelines as claimed in claim 1 in whichthe runs contain metallic elements for cathodic protection of thepipeline.

5. The safety installation for pipelines as claimed in claim 1 in whicheach run is provided with a fluid tight access chamber 6. The safetyinstallation for pipelines as claimed in claim 1 in which the spacingmeans are perforated so as to insure communications between thechannels.

1. In combination, a pipeline and a safety installation for preventingpollution of the pipeline environment through cracks in that pipeline,said combination comprising a pipeline section defining a plurality ofruns, a continuous jacket surrounding said pipeline section and sealedat its ends thereto, spacing means having channels therein providing anannular gap between said pipeline section and said jacket along whichliquid leaking from said pipeline section can flow, fluid tightpartitions dividing said annular gap into horizontal water-filled runsin which the water flows by repelling action of leakage liquid, andinclined adjacent gas-filled runs, in which the liquid flows by gravity,the water and gas in said runs being at the same constant pressure,which slightly exceeds atmospheric pressure, each said gas-filled runhaving at its lower end a leakage pipe connected to an individual closedcollecting vessel situated at a still lower level and also to a detectordevice which is reactive immediately to liquid in said leakage pipe,said gaps, said leakage pipe and said collecting vessel forming a sealedenclosure, and selective transfer devices acting to by-pass saidpartitions, each transfer device comprising a chimney partially filledwith water of a horizontal run and communicating over said water leverwith an inclined run.
 2. The safety installation for pipelines asclaimed in claim 1 including a short conduit between the chimney and theinclined run providing the communication over the water level with aninclined run, and instruments permanently monitoring the fluid tightnessof said enclosure.
 3. The safety installation for pipelines as claimedin claim 1 in which the liquid filling the channels of the annular gapof the horizontal run is demineralized water and the gas filling thechannels of the annular gap of the inclined run is an inert gas.
 4. Thesafety installation for pipelines as claimed in claim 1 in which theruns contain metallic elements for cathodic protection of the pipeline.5. The safety installation for pipelines as claimed in claim 1 in whicheach run is provided with a fluid tight access chamber.
 6. The safetyinstallation for pipelines as claimed in claim 1 in which the spacingmeans are perforated so as to insure communications between thechannels.